title: Antiviral mechanisms of human defensins.
abstract: Defensins are an effector component of the innate immune system with broad antimicrobial activity. Humans express two types of defensins, α- and β-defensins, which have antiviral activity against both enveloped and non-enveloped viruses. The diversity of defensin-sensitive viral species reflects a multitude of antiviral mechanisms. These include direct defensin targeting of viral envelopes, glycoproteins, and capsids in addition to inhibition of viral fusion and post-entry neutralization. Binding and modulation of host cell surface receptors and disruption of intracellular signaling by defensins can also inhibit viral replication. In addition, defensins can function as chemokines to augment and alter adaptive immune responses, revealing an indirect antiviral mechanism. Nonetheless, many questions regarding the antiviral activities of defensins remain. Although significant mechanistic data are known for α-defensins, molecular details for β-defensin inhibition are mostly lacking. Importantly, the role of defensin antiviral activity in vivo has not been addressed due to the lack of a complete defensin knockout model. Overall, the antiviral activity of defensins is well established as are the variety of mechanisms by which defensins achieve this inhibition; however, additional research is needed to fully understand the role of defensins in viral pathogenesis.
authors.affiliation: University of Washington School of Medicine, Box 357735, 1705 North East Pacific Street, Seattle, WA 98195, USA.
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Wilson
authors.forename: Mayim E
authors.initials: ME
authors.lastname: Wiens
authors.forename: Jason G
authors.initials: JG
authors.lastname: Smith
mesh_terms: D000998:Antiviral Agents / Q000276:immunology / Q000378:metabolism*; D023082:Defensins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D018448:Models, Immunological; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology*; D014779:Virus Replication; D014780:Viruses / Q000276:immunology*; D023084:alpha-Defensins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D023083:beta-Defensins / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D000998:Antiviral Agents; D023082:Defensins; D011956:Receptors, Cell Surface; D023084:alpha-Defensins; D023083:beta-Defensins
keywords: BK virus; BKV; CMV; DC; HAdV; HBD; HD; HIV; HNP; HPIV; HPV; HRV; HSV; IAV; LTB4; MBD; PBMC; PIV; PKC; RSV; SBD1; VSV; antimicrobial peptides; cytomegalovirus; defensin; dendritic cell; herpes simplex virus; human adenovirus; human defensin; human immunodeficiency virus; human neutrophil peptide; human papillomavirus; human parainfluenza virus; human rhinovirus; human β-defensin; influenza A virus; innate immunity; leukotriene B4; murine β-defensin; parainfluenza virus; peripheral blood mononuclear cell; protein kinase C; respiratory syncytial virus; sheep β-defensin 1; vesicular stomatitis virus; virus